Once a vehicle, such as an aircraft, has been placed in service, it may be necessary to periodically inspect and, if necessary repair or replace the components of the vehicle periodically. Such components may take the form of discrete electronic components, hydraulic components, wires and cables, other fittings, and bulkheads. Many of the components may be partially or entirely located within sealed enclosures on the vehicle. If a workpiece, such as one of these components, is located within a sealed enclosure or other limited-access area, the disassembly and reassembly of the structure surrounding the workpiece may be necessary in order to perform inspection, repair, or other actions, which is costly and time consuming.
As an alternative, structure, such as walls, enclosing such limited-accessed areas may include an access opening sized to receive a sensor, tool, or other instrument that enables a visual inspection of, or an operation to be performed on, the workpiece. If the interior of the structure surrounding the workpiece is relatively open, use of such a sensor, tool, or other instrument may be guided visually by a user. However, in many applications, such an enclosure may include an interior in which the workpiece may be obstructed by hardware or other structure that makes access and inspection difficult. Further, in such limited-access areas, the workpiece may be occluded by smoke, dust, or liquid, making it difficult to inspect or effect repair or replacement.
For example, certain internal aircraft structures may require in-service inspection, maintenance, and repair, but such structures may be obstructed by tubes, brackets and actuators that must be removed first. In some cases, initial inspections may take more than 1000 hours, and subsequent inspections may take more than 500 hours. Other internal aircraft components may be obstructed by other structural elements. Because of structural removal issues, an initial aircraft inspection may take more than 2000 hours, and recurring inspections as much as 1100 hours.
Typically, inspections may be performed using borescopes and remote cameras shaped to be inserted into limited access areas. Such devices may be able to see surface flaws or damage, but not subsurface damage. In many cases, features found using these devices and methods may be misdiagnosed as damage, and only determined to be benign markings after costly disassembly. Fatigue inspections of titanium attach fittings on aircraft may be programmed as visual borescope inspections, but if crack-like indications are found, there is no current method of confirming them other than simply disassembly of the structure.
With the increase in use of bonded and co-cured composite structures for aircraft, access to the interior for production and in-service inspection may be very difficult, costly, and time-consuming. Such inspection may be so expensive that certain lower-cost structure designs cannot be utilized because of the high cost of performing in-service inspections.
In addition, once a defect has been detected in such an enclosure, it may be necessary to effect repair. Typically, it is necessary either to enlarge the inspection opening, which may require removal of material or removal of a larger access plate, in order to perform a repair at the location of the defect. Such repair operations may be expensive due to the additional labor and cost of removal of structure in order to access the area of the defect.
Accordingly, there is a need for a system and method for nondestructive inspection in limited, enclosed areas that tracks the position and orientation of an inspection device in a confined space. There is also a need for utilizing tools in such limited enclosed areas to effect maintenance and/or repair without requiring enlarging the access opening, and without providing an operator with line-of-sight vision of the workpiece.